A brand new paper showing the Proceedings of the National Academy of Sciences offers new element and understanding to the cultivation of corn, one of many United States’ largest money crops.
The analysis by a crew on the University of Kansas facilities on “hybrid vigor,” also called “heterosis,” a widely known phenomenon the place crosses between inbred traces of corn and different crops produce offspring that outperform their dad and mom in yield, drought resistance and different fascinating qualities. Yet, the mechanisms underpinning heterosis are little understood regardless of over a century of intensive analysis.
The new PNAS analysis examines the connection between heterosis and soil microbes, displaying, typically, heterosis is facilitated by a microbial neighborhood.
“Hybrid vigor is super important in agriculture because one of the reasons for the great increases in crop productivity over the last several decades has been the use of hybrid cultivars, which tend to be much more productive and stronger and healthier than inbred cultivars,” stated lead creator Maggie Wagner, assistant scientist on the Kansas Biological Survey & Center for Ecological Research and assistant professor with the KU Department of Ecology & Evolutionary biology. “Despite how important this is we still don’t fully understand why hybrids are so superior to inbreds. A lot of focus has been on the genetics of hybrid vigor, which makes sense because hybridization is a genetic process—but there’s been some evidence the environment is important as well for affecting the strength of hybrid vigor. In this paper, we showed microbes living in the soil are one of the environmental factors that have a really important effect on hybrid vigor.”
In a sequence of experiments, Wagner and her co-authors discovered typically inbred guardian traces and hybrid crosses carry out equally underneath sterile circumstances, with out the presence of microbes—however heterosis “can be restored by inoculation with a simple community of seven bacterial strains.” The researchers noticed the identical outcomes for seedlings inoculated with “autoclaved versus live soil slurries in a growth chamber and for plants grown in steamed or fumigated versus untreated soil in the field.”
Wagner’s co-authors at KU had been Kayla Clouse and Laura Phillips. Other co-authors had been Clara Tang, Fernanda Salvato, Alexandria Bartlett, Simina Vintila, Manuel Kleiner, Mark Hoffmann, Shannon Sermons and Peter Balint-Kurti at North Carolina State University. Sermons and Balint-Kurti additionally work with the U.S. Department of Agriculture.
“In lab experiments, we essentially grew the plants inside plastic bags in order to provide a completely sterile environment for them,” Wagner stated. “That allowed us to completely control which microbes, if any, were interacting with the plants. So, it’s just some basic microbiology, along with a new kind of growth environment. But then in the field, we tried several different approaches to sterilize the soil, including just steam fumigation, which is used often, especially in fruit and vegetable production. It’s not really generally used for corn growth, but for this experiment it made sense for us to do that. And we tried some chemical fumigants as well, and got similar results with all those methods.”
In the soil-steaming experiment on the KU Field Station—which quickly eliminates or reduces microbes—the researchers discovered the steaming “increased rather than decreased heterosis, indicating that the direction of the effect depends on community composition, environment or both.”
“It’s complicated, and we don’t fully understand what’s going on yet,” Wagner stated. “The first three experiments all showed the exact same direction of the effect. But then for the fourth experiment, we again found that microbes influenced heterosis but it was in the opposite direction, where the hybrid had a more positive reaction to sterile conditions. We think that this could just be due to some something particular to the microbial community in the soil for this one experiment, but we’re not sure yet.”
The new paper is to be adopted by analysis in the identical vein supported by a $900,000 new grant from the National Science Foundation involving most of the similar personnel, with Wagner appearing as one of many principal investigators.
The grant work will comply with three traces of investigation: testing a variety of microbes for his or her skill to spice up hybrid vigor in corn; discovering genetic variants and areas of the corn genome that reply to soil microbes; and researching how microbes behave throughout the roots of inbred and hybrid corn on the molecular degree. The investigators hope their work might result in higher strategies in agriculture and conservation.
“We have this very basic observation of microbes affecting hybrid vigor, but we weren’t able to follow up on it without some funding—this grant is going to push the same line of research forward,” Wagner stated. “My collaborators are Manuel Kleiner at N.C. State who is an expert in metaproteomics, which is a way to measure the protein expression of microbes inside plant roots. We’re hoping to learn more about how hybrids and inbreds are interacting with microbes differently, possibly by influencing the microbes’ behavior. Our other collaborator is Peter Balint-Kurti with the USDA. He’s an expert in the maize immune system and the genetic basis of disease resistance, so he’s going to map some genes related to hybrids’ responses to microbes. Here at Kansas, a graduate student in my lab, Kayla Clouse, will look at some of the broader patterns of this phenomenon—for example, we don’t know yet if all maize hybrids will react to microbes in the same way. So far, we’ve only confirmed this in one hybrid, so we need to figure out how generalizable it is—and we’re also hoping to figure out what is it about the microbial community that that can affect this response in either direction. A lot of her future dissertation work will be related to this project.”
Maggie R. Wagner et al, Microbe-dependent heterosis in maize, (2020). DOI: 10.1101/2020.05.05.078766
University of Kansas
Research exhibits microbes play vital function boosting vigor of hybrid corn (2021, July 20)
retrieved 20 July 2021
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